Volume 14 Australasia - dana ward's homepage

362 AUSTEALASIA.heat and cold, wind and raiu, and in several places the surface has been excavatedmany tens and even hundreds of yards, leaving here and there masses of harderrocks, which indicate the original level of the novr vanished formations. Innorth-west Australia lies the region to which Gray has given the name of "PillarLand," from the myriads of sandstone columns rising above the surrounding plainswhich have been irregularly excavated. This region is carpeted with floweringplants and festooned with belts of verdure, while the work of erosion is still continuedby running waters partly flowing below the surface.About the very centre of the continent stands another of these geologicalwitnesses, which is known as " Chambers's Pillar," and which rises 150 feet abovean eminence itself about 100 feet higher than the surrounding plain. Thiscolumn, one of the most regular formations of the kind on the surface of the globe,forms a conspicuous landmark much utilised by the early explorers as a rallyingpoint, and convenient site for a cache or storehouse of provisions. It is about tenfeet by twenty in cross section, of nearly equal compass from top to bottom, andformed of a soft white sandstone like the hill on which it stands. The upper partof the pillar is of a red tint, and its preservation is perhaps due to the greaterhardness and durability of this topmost layer (Wallace).Like the Sahara, the Australian desert has its region of dunes stretching westof the overland telegraph on the north-west continental slope. Here the chainsof sandhills follow each other with perfect regularity, rolling away like the wavesof the sea for a distance of about 350 miles in the direction from east to west.Consisting entirely of red particles, without a blade of grass to relieve their fierceglare, these dunes are described by Sturt as producing a "terrible" effect, and notraveller ventures to traverse them without a sense of awe. Beyond this dreadedregion a few verdant and flowery oases are seen here and there in the drearywilderness. The aspect, however, of the Australian desert changes with the dryand wet seasons, so that the descriptions of the same district by different explorersoften present great discrepancies.The observations made by geologists on the main features of the continentalperiphery lend much probability to the hypothesis of a general upheaval of theAustralian seaboard. Its shores, after having been submerged under the waters,which at one time covered about half of the surface, were again gradually upr lisedabove the level of the surrounding seas. The coasts are fringed by upheavedbeaches, in which are embedded banks of shells similar to those still surviving inthe neighbouring waters. Numerous lakes, which were, till recently, marineinlets, have preserved their oceanic fauna, while others have been graduallychanged to freshwater basins, or have even been completely evaporated. Shoalsand reefs formerly concealed below the surface now show their black rocks abovethe level of the sea.A careful study of the whole region stretching to the north of Spencer Gulfleaves no doubt that this tract of dry land at one time formed an archipelago withnumerous islands separated from each other by shallow straits.Bass Strait itself,which forms the southern limit of Australia proper, would be changed to dry land